The Greek forward finished with 15 points, 12 rebounds and 11 assists.
Jabari Parker led the Bucks with 27 points, 10 of them in the third quarter as Milwaukee erased a seven-point halftime deficit.
After connecting on just three of 11 from three-point range in the first half, Milwaukee hit six from beyond the arc in the third.
Greek forward Antetokounmpo scored just one point in the period, but he pulled down three rebounds and handed out four assists.
He finished with 15 points, 12 rebounds and 11 assists.
"Some would say it wasn't a pretty game for him," Bucks coach Jason Kidd said. "But he's a winner and he helped his team find a way to win tonight by getting other guys involved.
"Being able to get a triple-double for us, I think his record is pretty good when he does that. He sets the tone for us, and again he set the tone for us today.
"Some would say his game, it wasn't pretty. But a win is a win. That is the maturity of a 22-year-old, that you can see a leader is growing right in front of us."
Matthew Dellavedova scored 17 points for Milwaukee, whose reserves contributed 40 points in the home win.
Damian Lillard led the Trail Blazers with 30 points, while CJ McCollum added 23. Allen Crabbe had 14 off the bench for Portland and hit a three-pointer with just under a minute remaining that trimmed the deficit to four.
A turnaround hook by Aussie guard Dellavedova stretched the Bucks' lead back to six points. Antetokounmpo and John Henson sank a pair of free throws each to close it out.
The Bucks, whose four-game winning streak was snapped Monday night against San Antonio, have won six of their last eight to improve to 11-9.
"We are rolling right now," Antetokounmpo said.